1. Field of the Invention
The present invention relates to a door mechanism provided to a cover of a machine tool having automatic pallet changers.
2. Description of Related Art
Machine tools such as machining centers are provided with a main spindle unit provided with a tool. The main spindle unit can be brought closer to and away from a table on which a pallet is placeable. A workpiece (object to be machined) is placed on the pallet on the table, and machined with the main spindle unit brought closer to the table. In such machine tools, automatic pallet changers are usually provided (arranged side by side) for transporting pallets with a workpiece mounted thereon onto and out of the table in order to change an unmachined workpiece and a machined workpiece in a short time.
In addition, such machine tools are normally provided with a cover that covers the periphery of the main spindle unit, the table, and so forth in order to prevent chips and a cutting fluid from being scattered. An opening portion is formed between the cover and the automatic pallet changers positioned outside the cover. A door mechanism is provided to open and close the opening portion. In the door mechanism, it is well known that a plurality of door panels are slid in the up-down direction or the left-right direction. Besides, other types of door mechanisms in which the door panels are folded rearward while sliding in the left-right direction as described in Japanese Unexamined Utility Model Application Publication No. 2-78245 is also known.